// // object  vs   Object   vs    {}

// let a: Object = '1'
// a = {}
// a = 1

// // let a2: String = void 0 //  大写的String叫装箱类型可以是本身以外的别的类型    小写的string叫拆箱类型只能是字符串
// // a2 = null

// let a3: object = undefined
// let a4: object = null
// let a5: object = void 0
// // let a6: object = '234'
// let a7: object = []
// let a8: object = () => {}


const a9: {} = {n: 1}
const a10: {} = undefined
const a11: {} = null
const a12: {} = void 0
const a13: {} = '234'
const a14: {} = []
const a15: {} = () => {}
